1、Designation: A800/A800M 10A800/A800M 14Standard Practice forSteel Casting, Austenitic Alloy, Estimating Ferrite ContentThereof1This standard is issued under the fixed designation A800/A800M; the number immediately following the designation indicates the yearof original adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers procedures and definitions for estimating ferrite content in certain grades
3、of austenitic iron-chromium-nickel alloy castings that have compositions balanced to create the formation of ferrite as a second phase in amounts controlledto be within specified limits. Methods are described for estimating ferrite content by chemical, magnetic, and metallographicmeans.1.2 The grade
4、s covered by this practice are: CF-3, CF-3A, CF-8, CF-8A, CF-3M, CF-3MA, CF-8M, CF-8C, CG-8M, andCH-10.1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in eachsystem are not exact equivalents; therefore, each system must be use
5、d independently of the other. Combining values from the twosystems may result in nonconformance with the practice.1.3.1 Within the text, the SI units are shown in brackets.1.4 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of
6、theuser of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitationsprior to use.2. Referenced Documents2.1 ASTM Standards:2A351/A351M Specification for Castings, Austenitic, for Pressure-Containing PartsA370A751 Test Methods Methods
7、, Practices, and DefinitionsTerminology for Mechanical TestingChemical Analysis of SteelProductsA799/A799M Practice for Steel Castings, Stainless, Instrument Calibration, for Estimating Ferrite ContentA941 Terminology Relating to Steel, Stainless Steel, Related Alloys, and FerroalloysE38A1067/A1067M
8、 Methods for Chemical Analysis of Nickel-Chromium and Nickel-Chromium-Iron AlloysSpecification forTest Coupons for Steel Castings (Withdrawn 1989)E353 Test Methods for Chemical Analysis of Stainless, Heat-Resisting, Maraging, and Other Similar Chromium-Nickel-IronAlloysE562 Test Method for Determini
9、ng Volume Fraction by Systematic Manual Point Count2.2 Constitution Diagrams:Schoefer Diagram for Estimating Ferrite Content of Stainless Steel Castings (1980 revision)3Schaeffler Diagram for Estimating Ferrite Content of Stainless Steel Weld Metal4DeLong Diagram for Estimating Ferrite Content of St
10、ainless Steel Weld Metal51 This practice is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.18on Castings.Current edition approved Oct. 1, 2010May 1, 2014. Published November 2010June 2014. Originally appr
11、oved in 1982. Last previous edition approved in 20062010 asA800/A800M 01 (2006).A800/A800M 10. DOI: 10.1520/A0800_A0800M-10.10.1520/A0800_A0800M-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standar
12、dsvolume information, refer to the standards Document Summary page on the ASTM website.3 Appendix of this practice.4 Metal Progress Data Book, American Society for Metals, Mid June 1977, p. 161.5 Welding Journal, American Welding Society, Vol 38, No. 7, July 1973, p. 293s.This document is not an AST
13、M standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In al
14、l cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.3 Americ
15、an Welding Society Specification:AWS A 4.2, Procedures for Calibrating Magnetic Instruments to Measure the Delta Ferrite Content of Austenitic Stainless SteelWeld Metal63. Terminology3.1 Definitions:3.1.1 ferritethe ferromagnetic, body-centered, cubic-microstructural constituent of variable chemical
16、 composition iniron-chromium-nickel alloys. This may be formed upon solidification from the molten metal (delta ferrite) or by transformationfrom austenite or sigma phase on cooling in the solid state (alpha ferrite).3.1.2 ferrite contentthe proportion of total volume of an iron-chromium-nickel allo
17、y present as the ferrite phase.3.1.3 ferrite numberthe ferrite content expressed as an arbitrary number based on the magnetic response of the alloy in a welddeposit.3.1.4 ferrite percentagethe ferrite content expressed as a volume percent.3.1.5 heat treatmentthe definitions in Terminology A941 are a
18、pplicable to this practice.4. Significance and Use4.1 The tensile and impact properties, the weldability, and the corrosion resistance of iron-chromium-nickel alloy castings maybe influenced beneficially or detrimentally by the ratio of the amount of ferrite to the amount of austenite in the microst
19、ructure.The ferrite content may be limited by purchase order requirements or by the design construction codes governing the equipmentin which the castings will be used. The quantity of ferrite in the structure is fundamentally a function of the chemical compositionof the alloy and its thermal histor
20、y. Because of segregation, the chemical composition, and, therefore, the ferrite content, may differfrom point to point on a casting. Determination of the ferrite content by any of the procedures described in the following practiceis subject to varying degrees of imprecision which must be recognized
21、 in setting realistic limits on the range of ferrite contentspecified. Sources of error include the following:4.1.1 In Determinations from Chemical CompositionDeviations from the actual quantity of each element present in an alloybecause of chemical analysis variance, although possibly minor in each
22、 case, can result in substantial difference in the ratio of totalferrite-promoting to total austenite-promoting elements. Therefore, the precision of the ferrite content estimated from chemicalcomposition depends on the accuracy of the chemical analysis procedure.4.1.2 In Determinations from Magneti
23、c ResponsePhases other than ferrite and austenite may be formed at certain temperaturesand persist at room temperature. These may so alter the magnetic response of the alloy that the indicated ferrite content is quitedifferent from that of the same chemical composition that has undergone different t
24、hermal treatment. Also, because the magnetsor probes of the various measuring instruments are small, different degrees of surface roughness or surface curvature will vary themagnetic linkage with the material being measured.4.1.3 In Determinations from Metallographic ExaminationMetallographic point
25、count estimates of ferrite percentage mayvary with the etching technique used for identification of the ferrite phase and with the number of grid points chosen for theexamination, as explained in Test Method E562.4.2 The estimation of ferrite percent by chemical composition offers the most useful an
26、d most common method of ferrite controlduring melting of the metal.4.3 For most accurate estimate of ferrite percent, a quantitative metallographic method should be used.5. Ordering Information5.1 Orders for material to this practice should include the following as required:5.1.1 Applicable ASTM pro
27、duct specification or other document covering product requirements,5.1.2 Alloy grade,5.1.3 Required ferrite content range, in volume percent, of the castings after final heat treatment. Also, if desired by thepurchaser, required ferrite content range, in ferrite number, for weld deposits (Note 1) as
28、 deposited, and5.1.4 Supplementary requirements, if any, desired.NOTE 1There may be a substantial decrease in the ferrite content of weld deposits after solution heat treatment in comparison with the as-depositedvalue.6. General Caution6.1 In specifying ferrite content as required in 5.1.3, the purc
29、haser should not set limits that conflict with applicable materialspecification requirements: for example, a maximum limit of 10 % ferrite for Grade CF-3A in Specification A351/A351M forwhich the minimum tensile strength requirement is 77 ksi 530 MPa.6 Available from American Welding Society (AWS),
30、550 NW LeJeune Rd., 8669 NW 36 Street, #130, Miami, FL 33126.33166-6672, http:/www.aws.org.A800/A800M 1426.2 When Supplementary Requirement S1 is specified, the purchaser should set ferrite content limits that are compatible withthe measuring instrument to be used.7. Estimation of Ferrite Content7.1
31、 Estimation in the base metal of the casting by chemical composition in accordance with the Schoefer diagram (see AppendixX1):7.1.1 A chemical analysis of the heat from which the castings are poured shall include the following elements whether or notrequired by the chemical requirements of the produ
32、ct specification: carbon, manganese, silicon, chromium, nickel, molybdenum,columbium, and nitrogen.7.1.1.1 Upon written agreement between the purchaser and the producer, an estimated nitrogen content may be reported insteadof an amount determined by analysis of the specific heat if actual chemical a
33、nalyses have been made for nitrogen in a sufficientnumber of heats of the same alloy type, produced by the same melting practice, to establish the average nitrogen content to beexpected.7.1.2 The ferrite content of the casting shall be estimated from the central line of the diagram at the compositio
34、n ratio of“chromium equivalent” (Cre) to “nickel equivalent” (Nie) determined from the following formula:Cr%!11.5Si%!11.4Mo%!1Cb%!24.99!/Ni %!130C%!10.5Mn%!126N 20.02%!12.77)5Cre!/Nie!7.1.3 When a product analysis is made by the purchaser, it shall include the elements listed in 7.1.1. If a comparis
35、on is madeof ferrite content estimated from a product analysis performed by the purchaser, with that estimated from the heat analysis (see7.1.1), the reproducibility data in the precision statements of Test Methods E353 shall be used as a guide.7.1.3.1 Test Methods E38A751 or Test Methods E353, as a
36、pplicable, shall be used as referee chemical analysis methods.7.2 Estimation in weld deposits by chemical composition in accordance with the Schaeffler or DeLong diagrams:7.2.1 The ferrite content shall be estimated (a) from the deposit chemical analysis included on the electrode manufacturerscertif
37、ied material test report, or (b) from chemical analysis of a weld deposit pad made by the casting manufacturer.7.3 Estimation of ferrite content in heat, product, or weld metal may be made by the magnetic response or metallographicmethods by imposition of Supplementary Requirements S1 or S2, respect
38、ively.8. Acceptance Standards8.1 Conformance with the required ferrite content range specified in 5.1.3 as indicated by the estimation procedure of 7.1 and7.2 shall be the basis for acceptance of material supplied under this practice unless other methods of estimation are ordered assupplementary req
39、uirements, in which case the supplementary requirement shall be the basis of acceptance.8.2 If lack of conformance with the ferrite content range specified in 5.1.3 is indicated by a product analysis made by thepurchaser (7.1.3) and by a referee analysis as provided in 7.1.3.1, rejection of material
40、 shall be subject to the tests of 7.3 asestablished by written agreement between the manufacturer and the purchaser.9. Certification9.1 The manufacturers certification shall be furnished to the purchaser stating that the material was sampled and tested inaccordance with the specification (including
41、year date) and was found to meet the requirements.9.2 The test report shall contain the results of the actual chemical analyses required by 7.1.1 and 7.2.1 and the indicated ferritecontent range.9.3 The test report shall be signed by an authorized agent of the manufacturer.9.4 The test report shall
42、be furnished within five working days of shipment of the castings.10. Keywords10.1 austenite; austenitic stainless steel; ferrite; Schoefer Diagram; steel castingsA800/A800M 143SUPPLEMENTARY REQUIREMENTSThe following supplementary requirements are for use when desired by the purchaser. They shallnot
43、 apply unless specified in the order, in which event the specified methods of ferrite contentestimation shall be employed by the manufacturer before shipment of the castings.S1. Estimation of Ferrite Content by Measurement of Magnetic ResponseS1.1 The ferrite content of the heat from which the casti
44、ngs are poured shall be estimated from measurements made by primaryor secondary instruments calibrated in accordance with the requirements of Practice A799/A799M. All measurements shall bemade on material after the solution heat treatment required by the applicable product specification, or, if any
45、subsequent solutionheat treatment is employed, then after the final solution heat treatment.S1.1.1 Location of measurementsbase metal:S1.1.1.1 Measurements shall be made on the unstrained ends of tension test specimens from the same heat as the castingsrepresented. Measurements may be made either be
46、fore or after performance of the tension test. If a tension test is not required bythe applicable product specification, measurements may be made on a specimen cut from a keel block of a design in Fig. 3 of TestMethods and Definitions any of the coupons shown in Test Coupons for Steel Castings A370A
47、1067/A1067M. , except for Fig. 3,or on one of the castings.S1.1.1.2 When further specified, measurements shall be made on the base metal of the castings, or a specified sample of castings(not on weld repairs or other weld deposits), in locations designated on the design drawing or as otherwise agree
48、d in writingbetween the purchaser and the manufacturer.S1.2 The ferrite content of weld deposits shall be estimated from measurements made by primary or secondary instrumentscalibrated in accordance with the requirements of Specification AWS A4.2. All measurements shall be made on weld deposits asde
49、posited.S1.2.1 Location of measurementsweld deposits:S1.2.1.1 Measurements shall be made on a weld pad deposited in accordance with the electrode specification.S1.2.1.2 When further specified, measurements shall be made on repair or fabrication welds on castings in locations as agreedin writing between the purchaser and manufacturer.S1.3 Number of MeasurementsSix measurements shall be made at random in each designated location. For instrumentshaving probes making two contacts with the surface being measured, a “measurement” shall consist of a pair
